The present invention relates generally to the field of electrosurgical instruments. More specifically, it relates to a device that electrosurgically fixes and identifies the location, in situ, of a pathologically suspect tissue mass in a patient's body, for facilitating the accurate surgical removal of the mass.
It is often medically desirable to remove a pathologically suspect tissue mass, such as a suspected tumor or lesion, from a patient's body. For example, in treating breast cancer, a suspicious tissue mass is typically identified and localized by imaging means, such as mammography or ultrasound. Once localized, the mass is typically subjected to a biopsy to determine whether or not it is malignant. Often, the biopsy will be an "open" biopsy, in which all or part of the identified mass is surgically removed, sometimes with a surrounding margin of tissue.
The identification and localization of the suspect mass is usually performed by a radiologist. The patient is then typically transported to an operating room for surgery. To allow the surgeon to be able to locate the identified mass, the radiologist places one or more localization wires or "Kopan's" wires into the breast to define and locate the tissue mass to be removed. In using a localization wire, a hollow needle or cannula, containing the localization wire, is inserted into the breast under local anaesthesia, while the breast is under compression during the imaging procedure, until the distal end of the localization wire passes through the suspect mass. The localization wire is anchored distally beyond the mass by means such as a barb or hook at the distal end of the wire. The cannula is then removed from the body, leaving the wire in place and extending from the body as a marker for the surgeon.
The above-described procedure has certain shortcomings, however. One problem stems from the fact that the localization wire is inserted while the breast is under compression during mammography. When the breast is released from compression, the distal end of the wire often migrates and thus shifts position with respect to the targeted tissue mass. This may lead to inaccurate placement of the incision for the biopsy, with the result that either an excess of tissue outside of the target tissue mass is removed, or less than all of the target tissue mass is removed. In addition, the wire is sometimes inadvertently shifted, severed, or pulled out during surgery, thereby defeating its purpose of accurately guiding the surgeon to the target tissue mass. Any inaccuracies in guiding the surgeon can result in larger than necessary amounts of healthy tissue being removed, with resultant deformation and scarring of the breast, or in the need to re-enter the incision site to remove parts of the target tissue mass that were missed on the first biopsy attempt.
Another shortcoming associated with prior art localization devices is that, while the location of the target tissue mass can be marked, no indication is provided of the dimensions of the mass. Thus, accurate removal of the desired amount of tissue depends on the surgeon's ability to determine the boundaries of the tissue mass during surgery.
It would therefore be advantageous to provide a localization device that minimizes or eliminates the aforementioned problems associated with the migration and inadvertent removal of the localization wire. It would be further advantageous for such a device to provide an accurate indication of the dimensions and boundaries of the target tissue mass. Furthermore, such a device should be easy to use, and should be compatible with existing imaging equipment and surgical methods.